Entangled two-photon absorption (ETPA) may be a viable technique to continuously drive an excited state population in plasma for high-bandwidth spectroscopy measurements of localized plasma turbulence or impurity density. Classical two-photon absorption commonly requires a high-intensity, pulsed laser, but entangled photons with short entanglement time and high time correlation may allow for ETPA using a lower intensity, continuous-wave laser. Notably, ETPA with non-collinear entangled photon generation allows for cross-beam spatial localization of the absorption or fluorescence signal using a single laser source. Entangled photon generation, the ETPA cross-section, candidate transitions for an Ar-II species, and plans for a proof-of-principle measurement in a helicon plasma are discussed.
@article{arxiv.2409.08391,
title = {Entangled two-photon absorption for the continuous generation of excited state populations in plasma},
author = {David R. Smith and Matthias Beuting and Daniel J. Den Hartog and Benedikt Geiger and Scott T. Sanders and Xuting Yang and Jennifer T. Choy},
journal= {arXiv preprint arXiv:2409.08391},
year = {2024}
}